1. Field of the Invention
The present invention relates to medical devices designed to assist a physician in performing a mediastinoscopy procedure. More specifically, the invention provides a kit of various systems that work together to improve access, sampling, and visualization during the procedure. Most specifically, the invention relates to inflatable devices for dilating a lumen or cavity in order to prepare a target site, including a mediastinal region, for access by instruments.
2. Description of the Related Art
The term mediastinoscopy refers to an examination of the mediastinum through an incision above and behind the sternum (breastbone) with a suprasternal incision. The mediastinum is the partition separating the right and left thoracic cavities. It is formed from the two inner pleural walls and includes all of the viscera of the thorax except for the lungs. More specifically, the organs in the mediastinal region include the heart and its vessels, the lymph nodes, the trachea, the esophagus, and the thymus. The individual devices and comprehensive self-sufficient kit of the present invention are designed to facilitate the process of inspecting, biopsying, and treating the mediastinum and surrounding areas to observe, detect, and ameliorate cancer or other abnormal tissue conditions.
A mediastinoscopy is an early stage or first step procedure performed in patients suspected of having lung cancer prior to thoracic surgery or other advanced therapy. Typically, a mediastinoscopy is performed to sample or biopsy lymph nodes in the paratracheal and parabroncial regions for cancer staging. Mediastinoscopy is also used to detect lymphoma, Hodgkin's disease, sarcoidosis (a chronic disease of unknown cause characterized by granulomatous tubercles or lesions of the lymph nodes, lungs, and other structures), and other conditions.
Problems with conventional devices and approaches for mediastinoscopy are numerous. First, traditional access is through a percutaneous incision in the neck. This leaves a visibly obvious, slow-healing, and painful scar through the many sensitive muscles and nerves in the neck. Second, visualization is typically poor and even with the assistance of an endoscopic monitor and ultrasound, skilled surgeons have difficulty accessing nodes and assessing whether a node, nodule, or tumor they are about to resect or sever from surrounding tissue is in fact the intended target. Additionally, operating within dark narrow working spaces increases the risk that the surgeon will inadvertently injure or at least aggravate critical vulnerable structures (including coronary arteries, valves, the heart itself) or puncture a lung in the same general region as the nodes while trying to reach the nodes. Third, the elongated instruments presently available require reaching out to grasp nodes, cutting, and dangling the severed, potentially abnormal tissue within the cavity prior to removal. This method risks dropping the sample prior to removal and can cause scattering of malignant particulate material for redistribution in the body amongst healthy tissue.
U.S. Pat. No. 7,232,414 (from hereon “USP '414”) entitled “System and method for capturing body tissue samples” by Hugo X. Gonzalez and assigned to Spiration, Inc. (Redmond, Wash.) discloses a system and method that reduces the risk of scattering abnormal cells during sampling. The system includes a bag means with an open end for receiving a sample and a vacuum suction tube for first pulling a portion of tissue into a protected cove prior to resecting and then for drawing the resected portion to a proximal end of the instrument for removal, collection, and histological analysis. This system and method however, do not address improving the initial visualization of and access to nodes in crevices or at angles out of the direct trajectory through which an instrument has been inserted.
U.S. Pat. No. 6,852,108 (from hereon “USP '108”) entitled “Apparatus and method for resecting and removing selected body tissue from a site inside a patient” by Robert Lawrence Barry, et al. and also assigned to Spiration, Inc. also focuses on reducing the chance of scattering material while resecting a sample. USP '108 elaborates to a greater extent than USP '414 on the position and design of an electrode used for resecting and on a collection chamber at the proximal end of the instrument with a plurality of compartments for indexing samples and preventing cross-contamination. For example, FIG. 9 shows electrode 100 housed within the protected interior of resection lumen 115 into which the vacuum draw 105 directs a portion of tissue (left upper paratracheal node 71l) prior to it being contacted by the electrode. The blade electrode may be made extendable as shown in FIG. 10. Alternatively, it may be designed in the shape of a lasso 120 to form a loop 122 as shown in FIG. 13. In any case, all of the action takes place inside the resection lumen 115 of the tubular member 92 (FIGS. 7-15 are illustrative). The tubular member is inserted percutaneously through the skin after “making an incision at the sternal notch 27 just above the sternum 25” and it is placed “through the incision and between the trachea 28 and the top of the sternum 25” (7:19-34 and FIG. 6). There is no mention of using natural orifices to deliver the tubular member. There is also no disclosure of dilation elements or balloons to protect the trachea, sternum, etc. from agitation by the tubular member. A built-in improved viewing component is not taught as part of the device (7:31-34).
U.S. Pat. No. 5,941,819 (from hereon “USP '819”) entitled “Apparatus for creating a mediastinal working space” by Albert K. Chin and assigned to Origin Medsystems, Inc. (Menlo Park, Calif.) focuses more precisely on space creation in the mediastinal cavity. However, the system provided is a mechanical lifting retractor with two sharply angled rotatable arms (14a, 14b) rather than a pneumatically inflatable assortment of curved balloons. Further, the method provided is aimed at creating a working space for cardiac surgery specifically by “temporarily expanding the space between the rib cage and the pericardium” and involves insertion between a pair of adjacent ribs (FIGS. 7-8 and Abstract). There is no mention of the trachea or bronchus.
Very few patents are directed specifically at instruments and methods for performing a mediastinoscopy as indicated by reference to “mediastinoscopy” in the claims. U.S. Pat. No. 7,473,530 (from hereon “USP '530”) entitled “Method to detect lung cancer” by Maik Huttemann and assigned to Wayne State University (Detroit, Mich.) discloses methods of detecting cancer that involve comparing the levels of RNA for a specific component (COX4-2) in a first lung sample suspected to have cancer and a second lung sample known not to have cancer. The claims include a reference to “mediastinoscopy” along with several other possible diagnostic tests in the context of performing at least one additional test to confirm the lung cancer diagnosis based on the results of the first test comparing RNA (claim 20).
Similarly, there are relatively few United States patents referring to the “mediastinum” in the claims and of those that do almost all are directed at imaging methods, data analysis, or pharmaceutical treatment.
No patents can be found directly addressing atraumatic mechanical dilation of the mediastinal space.
With respect to the preferably toroidal design of the dilating element, U.S. Pat. No. 6,053,891 (from hereon “USP '891”) entitled “Apparatus and methods for providing selectively adjustable blood flow through a vascular graft” teaches that the mediastinum is exposed in order to install a shunt by dividing the sternum. However, the patent is not directed at mediastinoscopy procedures. It cites to U.S. Pat. No. 3,730,186 (from hereon “USP '186”) by Edmunds, et al. for disclosing the use of a “toroidal balloon” to occlude a native artery by placing the balloon around the outside of the artery. It teaches away from the use of a toroidal balloon because it is “believed to create crimps or infolds in the arterial wall even at low degrees of constriction” and “[s]uch crimps or infolds, which project into the flow field of the artery, are expected to disrupt laminar flow within the artery and serve as thrombogenic sites” (2:64-3:11). In the present invention this crimping problem would be avoided as the toroidal balloons herein are used inside conduits as dilators rather than outside conduits as occluders. Further, the toroidal balloons of the present invention are designed for use in larger conduits, canals, and cavities where they are not likely to be in the path of blood flow, rather than being used within or around the outsides of arteries and other blood vessels.
It would not be obvious to use toroidal balloons inside cavities and conduits as dilators including in the area alongside the trachea and in the pleural region. In the patent literature concerning medical devices and toroidal balloons they appear to be disclosed exclusively as occluders on the outside for preventing distal embolization around the heart. For example, see U.S. Pat. No. 7,458,980, U.S. Pat. No. 7,452,352, U.S. Pat. No. 7,396,329, U.S. Pat. No. 7,374,561, U.S. Pat. No. 7,335,192, etc.
None of the above patents provide systems, kits, or methods to dilate, easily sample, and improve visualization in the region outside the trachea during a mediastinoscopy procedure. Further, none of the above patents suggest accessing nodules on the outer trachea, bronchi, mediastinum, or lymph nodes without a neck incision by way of a natural orifice (including the mouth or nose) and natural lumens (including the throat and bronchi).